1. Field of Technology
The present invention relates generally to methods and apparatus for distribution of information and, more specifically is related to electronically displaying content in a display with sequenced color illumination.
2. Description of Related Art
As computer appliances become smaller, more mobile, and more computational, color displays that are small, have higher pixel count, i.e., better resolution, are less expensive and more energy efficient, are highly desirable. Digital wristwatches and other miniaturized video capable appliances, telephone screens, personal digital assistant computers (PDAs), portable miniature televisions, dedicated digital video disk players (DVDs), and other small, mobile devices with resolutions in pixels-per-inch (ppi) that approach the resolution limits of the eye should become the norm.
Prior flat panel display technologies, such as liquid crystal (LCD), field emission, plasma, microcapsule, organic light-emitting diode, and the like, each have limitations, especially for color resolution and cost. In part, these limitations result from their need for color mosaic imaging, where the picture elements (pixels) in such devices are generally only capable of rendering one of the three display primary colors. Two-to-four times as many pixels are thus required in a color mosaic to be resolved in the produced image.
Prior art display technologies suffer from further limitations in addition to shortcomings in available resolution and cost. Flat panel field emission and plasma displays operate under vacuum, making their use and cost prohibitive for most low cost, mobile applications. As one example, organic light emitting diode displays suffer from poor image brightness and have comparatively limited operation lifetimes. As another example, LCDs have slow pixel response times and poor off-axis viewability. The slow pixel response times derive from the movement of 1-to-30 micron particles in a liquid cell. The typical, and resultant, 20-to-45 millisecond (ms) pixel switching times often create image trails in video imaging and in scrolling text. Smaller but faster moving particles generally will produce unacceptable image contrast. The need for polarizers in LCDs reduces display illumination efficiency and off-axis viewability.
In standard display technology, another deficiency is a tradeoff between grayscale capability—i.e., the ability to create a continuous spectrum of colors via chromaticity—hue and saturation—variation and resolution. LEDs produce spectrally narrower and calorimetrically more saturated color than the phosphors, illuminating chemistries, and organic filters used in field emission and plasma, and liquid crystal displays, respectively. The number of possible colors produced through the addition of spectrally different illuminants is proportional to the spectral narrowness of the illuminants.